Support for an electronic box used for monitoring the tire pressure, mounted on a wheel rim of a motor vehicle

ABSTRACT

A support ( 11 ) that is mounted on a wheel rim of a motor vehicle in order to fasten an electronic box ( 10 ) used for monitoring the tire pressure. The support includes: a central part that is fixed to the rim; a first end which is provided with attaching elements for receiving a rotating shaft fastened to a first end of the box that is to be fixed; and a second end ( 18 ) that is provided with a plurality of elastically deformable retaining element ( 20, 25 ) for fixing a second end ( 17 ) of the electronic box to the support ( 11 ), each retaining element ( 20, 25 ) counteracting a specific force that is applied to the box.

The present invention relates to a support mounted on a rim of a motor vehicle, to hold in position an electronic unit for monitoring tire pressures. More specifically, such a support is intended to be fixed inside the rim of a tire.

It is already known practice for motor vehicle tires to be equipped with tire pressure monitoring means. These monitoring means are contained in a unit which has of course to be fixed inside each tire. To do this, this unit is sometimes adhesively bonded or irreversibly attached to the rim, but when the unit needs to be changed, it is impossible to detach it from the rim without destroying it.

The present invention proposes to remedy these disadvantages by creating a support bonded or fixed to the rim and in which the unit is placed. Thus, when the unit needs to be removed in order to repair it or to change its battery, it will be possible to remove the unit without destroying it.

The support for holding the unit inside the rim needs to be simple to produce and engineered in such a way that the forces applied to the unit as the wheel rotates do not damage it and do not adversely affect the quality of the measurements taken by the tire pressure monitoring system. These centrifugal forces may be very high (of the order of 2000 g).

To this end, the support according to the invention comprises:

-   -   a central part secured to the rim,     -   a first end equipped with catching means for a pivot pin secured         to a first end of the unit that is to be secured, and     -   a second end equipped with a plurality of elastically deformable         retaining means for securing a second end of the electronic unit         to the support, each retaining means being designed to counter a         specific force exerted on the unit.

Thus all the forces applied to the support are countered by different retaining means, each designed to suit a specific force.

Advantageously, the centrifugal force (which is the largest force) is countered by a central device with an elastic push fit. This central device is generously engineered toward satisfactorily performing this function. The vibrations and the stresses of shocks transmitted by the rim as the wheel rotates are, for their part, countered by a pair of lateral devices with an elastic push fit. These vibrations are lower in magnitude than the centrifugal force and the lateral devices are advantageously of smaller size. Furthermore, this pair of lateral devices applies a tension to the unit more or less at right angles to the central device thus enhancing the retention of the central device.

It will be noted that by dissociating the retaining means that combat the centrifugal force from the retaining means that combat the other forces applied to the system, it is possible more effectively to combat all the forces applied without overengineering the support.

It will also be noted that by using lateral devices collaborating with a central device there is no need to use a screw (or similar fastener) to immobilize this central device.

Advantageously, the lateral devices and the central device are produced as a single component, for example as a steel sheet pressing. The central device is therefore held in position (more specific immobilized) without the need to use additional components.

Other objects, characteristics and advantages of the present invention will also become apparent from the description which will follow, by way of nonlimiting example, with reference to the attached drawings in which:

FIG. 1 is a schematic side view depicting an electronic unit immobilized in position in a support according to the invention,

FIG. 2 is a schematic perspective view of the assembly consisting of the unit and the support according to the invention, showing the pivot pin A about which the unit pivots relative to the support,

FIG. 3 is a schematic view on a larger scale of the part of the support that bears the plurality of retaining means according to the invention, and

FIG. 4 is a schematic side view of the detail depicted in FIG. 3, more specifically showing a lateral device in an immobilizing position.

According to the embodiment shown in FIGS. 1 to 4, an electronic unit 10 is positioned on a support 11 the central part 11 a of which is bonded 12 (or secured by any appropriate means) against the internal face of a rim 13. The unit is thus fixed inside a tire (not depicted). This unit contains at least one pressure sensor (but it may also contain a temperature sensor, an acceleration sensor, etc.) and all the electronics needed for processing the signal from this sensor. The electronic unit also contains a device for emitting a signal to a central unit (generally situated in the cabin of the vehicle).

The support 11 according to the invention is designed to accept the unit 12 and for this purpose has two ends 14 and 18. A first end 14 is equipped with a catching means 16 (FIG. 2) which wraps around a pivot pin A formed in a first end 15 of the unit.

The unit 10 is made of plastic and producing this pivot pin at one of its ends presents no difficulty. This pivot pin forms an integral part of the unit.

The support 11 is, for its part, made of pressed sheet steel and the catching means 16 are also easy to manufacture. These catching means 16 form an integral part of the support.

When the unit 10 is being fitted, the pivot pin A is introduced into the catching means 16 and the unit pivots about its pin in the direction of the arrow F (FIG. 1) until it is positioned against the support 11.

During this pivoting movement, the second end 17 of the unit comes into contact with the second end 18 of the support. This second end of the support is equipped with a plurality of retaining means 20, 25 (FIGS. 4 and 5) to hold the unit in place in the bottom of the support and immobilize it in this position.

It will be noted that, as the wheel rotates, the unit (which weighs a few tens of grams) is subjected to a centrifugal force C that tends to pull it out of its support (FIG. 2). This centrifugal force C (represented by a thick arrow in FIG. 2) may be 2000 g, that is to say of the order of 2×10⁴ Newtons. In order to resist the pulling-out of the unit from its support, a central device 20 with an elastic push fit (see FIGS. 3 and 4) is provided. This central device is generously engineered toward countering the centrifugal spinning loadings. In particular, it exhibits an elastically deformable element 21 that clicks into a shoulder 22 provided for this purpose in the unit 10. In so doing, the unit is immobilized on the support against the action of the centrifugal force. The stronger the centrifugal force C, the stronger the immobilization.

The unit 10 is, however, subjected to other forces V (transverse forces—substantially perpendicular to the centrifugal forces) due to the stresses of vibrations and the stresses of shocks (FIG. 2) exerted on the tires as the vehicle moves along. To combat these stresses V, the central device is of no effect. These vibrations could even shift the element 21 from the shoulder 22 and thus release the unit (which would be most annoying!).

According to the invention, a pair of lateral devices 25 with an elastic push fit limits and prevents the transverse movements of the unit with respect to the support. These lateral devices (formed as an integral part of the support 11) have an elastic element 26 that clips onto a shoulder 27 produced on the side of the unit. These lateral devices therefore immobilize the unit in its support, that is to say force the unit to be pressed firmly against the support by applying to it a tension more or less perpendicular to that of the central device. Thus, the central device and the lateral devices collaborate with one another to hold and immobilize the unit in its support.

As the lateral stresses are lower in magnitude than the centrifugal force, these lateral devices may be smaller in size than the central device.

Furthermore, the immobilization of the lateral devices on the end 17 of the unit creates a stressing of the central device. The latter thus finds itself pressed forcibly against the shoulder 22, thus enhancing the immobilizing effect produced by the central device.

The plurality of retaining means according to the invention therefore consists of a central device (combating the centrifugal force) and a pair of lateral devices combating the stresses of vibrations and shocks.

By dissociating the retaining means according to the forces that are to be countered, it is possible to better engineer each of the retaining means. The plurality of retaining means according to the invention thus allows the loadings affecting the unit to be dissociated from one another. Thus, the centrifugal loadings are dissociated from the stresses of shocks and vibrations. A generously engineered (sized) central device provides a safeguard against centrifugal forces whereas two other, smaller, devices stress the central device against the unit in such a way as to compress it against the shoulder 22. Once in position, these three devices provide resistance to vibration and to centrifugal loadings without the need to resort to a screw or any other locking component.

Advantageously, these various retaining means act in different directions and are produced as one single component (namely the support). There is therefore no need to provide additional fastenings (for example a screw) in order effectively to immobilize the central device that combats the centrifugal force.

It will be noted that the retaining means are readily produced by the operation of pressing the steel sheet that acts as the support. The bending of the various parts toward one another thus easily providing positional immobilization in the various directions.

The elastic elements 21 and 26 can be disengaged from their respective shoulders 22 and 27 simply using an appropriate release tool (screwdriver) if necessary (for example when removing the unit). The unit 10 is then released from its support without damage. To this end, recesses (in the unit or in the support) may be created (in a way known per se) to leave the space required for the release tool.

Of course, the present invention is not restricted to the embodiment described. Thus the shapes of the retaining means may differ from those depicted provided that they provide an elastic push fit of the unit into the support (or vice versa). 

1. A support (11) mounted on a rim (13) of a motor vehicle, to hold in position an electronic unit (10) for monitoring tire pressures, said support being characterized in that it comprises: a central part (11 a) secured to the rim, a first end (14) equipped with catching means (16) accepting a pivot pin (A) secured to a first end (15) of the unit that has to be secured, and a second end (18) equipped with a plurality of elastically deformable retaining means (20, 25) for securing a second end (17) of the electronic unit to the support (11), each retaining means (20, 25) being designed to counter a specific force exerted on the unit.
 2. The support as claimed in claim 1, characterized in that the plurality of retaining means consists of a central device (20) with an elastic push fit combating the centrifugal force and of a pair of lateral devices (25) with an elastic push fit combating the stresses of vibrations and shocks transmitted to the unit as the rim rotates, said lateral devices (25) also being designed to immobilize the central device (20) under stress and to press the electronic unit (10) firmly against the support (11).
 3. The support as claimed in claim 2, characterized in that the lateral devices (25) stress the central device against the unit by applying a tension more or less at right angles to the central device.
 4. The support as claimed in claim 1, characterized in that the central device and the pair of lateral devices are made as one single component.
 5. The support as claimed in claim 1, characterized in that it is made of steel sheet through a pressing operation.
 6. The support as claimed in claim 2, characterized in that the central device and the pair of lateral devices are made as one single component.
 7. The support as claimed in claim 3, characterized in that the central device and the pair of lateral devices are made as one single component.
 8. The support as claimed in claim 2, characterized in that it is made of steel sheet through a pressing operation.
 9. The support as claimed in claim 3, characterized in that it is made of steel sheet through a pressing operation.
 10. The support as claimed in claim 4, characterized in that it is made of steel sheet through a pressing operation. 